Electrical equipment and device protection methods

Abstract

A power supply circuit, a printing device, a device protection method, and an electrical device are provided that, when a voltage outside a predetermined range is applied to the electrical device, allow a user to quickly recognize the situation. [Solution] In the electrical device 1, the power supply circuit 12 includes a voltage determination circuit 21 that determines whether the voltage applied through the jack 11 of the electrical device 1 is outside a preset allowable voltage range, a power switch 22 that electrically connects or disconnects the jack and the main circuit of the electrical device in response to operation by the user, and a switch control circuit 24 that has a holding member that holds the power switch so as to electrically disconnect the jack and the main circuit of the electrical device when it is determined that the voltage is outside the allowable voltage range.

Description

[Technical Field]

[0001] The disclosure herein is Electrical equipment and How to protect equipment By law Regarding. [Background technology]

[0002] Electrical devices that can be powered using an AC adapter are now widely used. AC adapters generally convert the AC voltage from a commercial power source into a specified DC voltage and output it. However, the DC input jack of an electrical device does not necessarily support only the AC adapter that is compatible with that electrical device. In other words, an AC adapter that generates a voltage incompatible with the electrical device may be connected to the DC input jack of the electrical device. If an AC adapter that generates a voltage higher than the specified voltage is connected to the electrical device, overvoltage may occur, potentially causing damage to the electrical device's circuits.

[0003] In response to this, configurations have been proposed to prevent overvoltage. For example, the power supply circuit described in Patent Document 1 includes a switch circuit on the input side of the load circuit. When the input voltage exceeds a predetermined value, the switch circuit is controlled to an off state, and the power line is cut off. This configuration can prevent damage to the load circuit due to overvoltage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-215681 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional configurations (e.g., the power supply circuit of Patent Document 1), when an overvoltage is applied to an electrical device, the power line is interrupted, causing the electrical device to stop working. However, in such cases, the user may not be able to identify the reason why the electrical device is not working. As a result, some users may not believe that the AC adapter is the cause, and so they may leave the AC adapter connected to the electrical device while searching for a solution, which requires a lot of effort and burden until they discover the cause. In addition, the user may repeatedly plug and unplug the AC adapter or press the start button (or power switch) of the electrical device multiple times. In these cases, the electrical device is subjected to a load, and in some cases the start button may malfunction, making it impossible to start the device again. Note that the above problem can occur not only when an overvoltage is applied to an electrical device, but also when a voltage lower than the expected voltage is applied to the electrical device.

[0006] Thus, in the prior art, when an incorrect AC adapter is connected and an overvoltage or undervoltage is applied to an electrical device, the user may not realize why the electrical device is not working, which can result in extra effort or burden before the electrical device can be operated.

[0007] An object according to one aspect of the present invention is to provide a configuration and method that can promptly let a user recognize a situation when a voltage outside a predetermined range is applied to an electrical device. [Means for solving the problem]

[0008] An electrical device according to one aspect of the present invention includes a voltage determination circuit that determines whether a voltage applied via a jack of the electrical device is outside a preset allowable voltage range; a notification unit that notifies a user that the voltage is outside the allowable voltage range when it is determined that the voltage is outside the allowable voltage range; a power switch that electrically connects or disconnects the jack and the main circuit of the electrical device in response to operation by the user; and a power switch that electrically disconnects the jack and the main circuit of the electrical device when it is determined that the voltage is outside the allowable voltage range, and that operates the power switch when the voltage changes to within the allowable range while the jack and the main circuit of the electrical device are electrically disconnected. The aforementioned User by On / Off The operation and a switch control circuit having a holding member for enabling the switch. [Effects of the Invention]

[0009] According to the above-described aspect, when a voltage outside a predetermined range is applied to an electrical device, it is possible to allow a user to quickly recognize the situation. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating an example of an electrical device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating an example of a power switch and a switch control circuit. [Figure 3] 10A and 10B are diagrams illustrating another example of an electrical device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] FIG. 1 shows an example of an electrical device according to an embodiment of the present invention. The electrical device 1 according to the embodiment of the present invention is not particularly limited, but in this example it is a label printer. The label printer can print desired characters, graphics, etc. on a label in response to a user's instruction. The printing method of the label printer is not particularly limited, and may be a thermal method using thermal tape or a thermal transfer method using an ink ribbon. The label printer is also called a label writer.

[0012] As shown in Fig. 1, the electrical device 1 includes a DC input jack 11, a power supply circuit 12, a main circuit 13, and a battery 14. Note that the electrical device 1 may also include other circuits or devices not shown in Fig. 1. For example, the electrical device 1 may have a function for communicating with an information processing device such as a smartphone.

[0013] A plug 15a of an AC adapter 15 is inserted into the DC input jack 11. The AC adapter 15 converts the AC voltage of a commercial power source into a predetermined DC voltage and outputs it. Therefore, when the AC adapter 15 is connected to a commercial power source and the plug 15a is inserted into the DC input jack 11, the predetermined DC voltage generated by the AC adapter 15 is applied to the electrical device 1.

[0014] The power supply circuit 12 is provided between the DC input jack 11 and the main circuit 13, and supplies power to the main circuit 13. The power supply circuit 12 also has a function of determining whether the voltage applied to the electrical device 1 is appropriate. In other words, the power supply circuit 12 can determine whether the AC adapter 15 connected to the DC input jack 11 is appropriate.

[0015] The main circuit 13 is a main part of the electrical device 1 and provides the functions of the electrical device 1. For example, if the electrical device 1 is a printing device such as a label printer, the main circuit 13 includes an input device that accepts user instructions, a printing device that prints characters or figures specified by the user on a label, and the like.

[0016] The battery 14 is provided to supply power to a predetermined circuit within the electrical device 1. For example, the battery 14 supplies power to a clock function of the electrical device 1. The battery 14 can supply power to a predetermined circuit even when the AC adapter 15 is not connected to the electrical device 1. The battery 14 may be mounted inside the main circuit 13 or outside the main circuit 13.

[0017] 1, the power supply circuit 12 includes a voltage determination circuit 21, a power switch 22, a notification unit 23, and a switch control circuit 24. The power supply circuit 12 may include other circuits not shown in FIG.

[0018] The voltage evaluation circuit 21 determines whether the DC voltage applied via the DC input jack 11 of the electrical device 1 is outside a predetermined allowable voltage range, and generates a evaluation signal indicating the result of the evaluation. In the following description, the DC voltage applied via the DC input jack 11 of the electrical device 1 may be referred to as the "input voltage."

[0019] The predetermined allowable voltage range is set based on the configuration or specifications of the main circuit 13. For example, if the main circuit 13 can operate normally when the input voltage is between 5V and 18V, the voltage evaluation circuit 21 determines whether the input voltage is between 5V and 18V. If the input voltage is within the range of 5V and 18V, the voltage evaluation circuit 21 outputs an H-level signal. On the other hand, if the input voltage is lower than 5V or higher than 18V, the voltage evaluation circuit 21 outputs an L-level signal. In this case, the H-level signal is an example of a determination signal indicating that the DC voltage applied via the DC input jack 11 of the electrical device 1 is within a predetermined allowable voltage range. The L-level signal is an example of a determination signal indicating that the DC voltage applied via the DC input jack 11 of the electrical device 1 is outside the predetermined allowable voltage range.

[0020] The voltage evaluation circuit 21 is realized by a commercially available integrated circuit such as, but not limited to, the LTC4365 (manufactured by Analog Devices). In this case, the desired lower and upper limit voltages (i.e., the desired allowable voltage range) can be set by appropriately determining the resistance value of the resistor connected to the control terminal of this integrated circuit. The voltage evaluation circuit 21 may operate on power supplied from the AC adapter 15 or the battery 14.

[0021] The power switch 22 electrically connects or disconnects the DC input jack 11 and the main circuit 13 in response to operation by the user of the electrical appliance 1. That is, the user can start or stop the electrical appliance 1 by operating the power switch 22. Thus, one terminal of the power switch 22 is electrically connected to the DC input jack 11, and the other terminal of the power switch 22 is electrically connected to the main circuit 13. The power switch 22 is realized by, but is not limited to, a push-button switch. In this case, when the power switch 22 is pressed while the electrical appliance 1 is in an off state, the DC input jack 11 and the main circuit 13 are electrically connected, and the electrical appliance 1 is started. Conversely, when the power switch 22 is pressed while the electrical appliance 1 is in an on state, the DC input jack 11 and the main circuit 13 are electrically disconnected, and the electrical appliance 1 is stopped.

[0022] When a determination signal indicating that the input voltage is outside a predetermined allowable voltage range is generated, the notification unit 23 notifies the user that the input voltage is outside the predetermined allowable voltage range. That is, when the determination signal output from the voltage determination circuit 21 is at L level, the notification unit 23 notifies the user that the input voltage is outside the predetermined allowable voltage range. In this embodiment, in order to visually notify the user of an abnormality in the input voltage, the notification unit 23 includes resistors R1 to R5, transistors TR1 and TR2, and a light-emitting element LED. The circuit configuration of the notification unit 23 is, for example, as follows:

[0023] The collector of transistor TR1 is connected to a power supply VBAT via resistor R1. The power supply VBAT corresponds to a battery 14. The base of transistor TR1 is connected to the output terminal of a voltage determination circuit 21 via resistor R2. The emitter of transistor TR1 is grounded. The output terminal (i.e., the collector) of transistor TR1 is connected to the gate of transistor TR2 via resistor R3. The gate and source of transistor TR2 are connected to each other via resistor R4. Resistor R5 and light-emitting element LED are connected in series between the drain of transistor TR2 and the power supply VBAT. The source of transistor TR2 is held at a predetermined potential VE.

[0024] The switch control circuit 24 maintains the power switch 22 in the OFF state when it determines that the input voltage is outside the allowable voltage range. In this embodiment, the switch control circuit 24 maintains the power switch 22 in the OFF state when a determination signal indicating that the input voltage is outside the allowable voltage range is generated. At this time, the switch control circuit 24 may prevent the DC input jack 11 from being electrically connected to the main circuit 13. Alternatively, the switch control circuit 24 may prevent the power switch 22 from being physically depressed. In other words, the switch control circuit 24 prevents the power switch 22 from being depressed to a position where the DC input jack 11 and the main circuit 13 are electrically connected. In other words, the switch control circuit 24 has a holding member that holds the power switch 22 so that the DC jack and the main circuit 13 are electrically disconnected.

[0025] Next, the operation of the power supply circuit 12 will be described. First, when a genuine AC adapter 15 is connected to the electrical device 1, the input voltage of the electrical device 1 falls within a predetermined allowable voltage range, and the determination signal output from the voltage determination circuit 21 is maintained at a high level. In this case, the transistor TR1 is controlled to an on state, and the gate of the transistor TR2 is controlled to a low level. This causes the transistor TR2 to be controlled to an off state, and no current flows through the light-emitting element LED. As a result, the light-emitting element LED does not emit light. Furthermore, when the determination signal is maintained at a high level, the switch control circuit 24 does not restrict the operation of the power switch 22. In other words, the power switch 22 can electrically connect or disconnect the DC input jack 11 and the main circuit 13 in response to a user instruction. In other words, the power switch 22 can turn the electrical device 1 on and off.

[0026] On the other hand, if an incorrect AC adapter 15 is connected to the electrical device 1 and the input voltage of the electrical device 1 falls outside the predetermined allowable voltage range, the determination signal output from the voltage determination circuit 21 is held at L level. In this case, the transistor TR1 is controlled to the OFF state, and the gate of the transistor TR2 is controlled to H level. This then controls the transistor TR2 to the ON state, causing current to flow through the light-emitting element LED. As a result, the light-emitting element LED emits light. Furthermore, when the determination signal is held at L level, the switch control circuit 24 holds the power switch 22 in the OFF state. In other words, even if the user operates the power switch 22, the electrical device 1 will not start up.

[0027] As described above, in the electrical device 1 according to the embodiment of the present invention, if the user uses an incorrect AC adapter 15 and the input voltage falls outside the predetermined allowable voltage range, the light-emitting element LED emits light. Therefore, the user can easily recognize that the input voltage is overvoltage or undervoltage. As a result, it is possible to avoid situations in which the electrical device 1 is left in an overvoltage or undervoltage state. In addition, since the user can immediately recognize that the AC adapter 15 connected to the electrical device 1 is inappropriate, the effort or burden required to operate the electrical device 1 normally is reduced. Furthermore, since the user can recognize that the input voltage is overvoltage or undervoltage before starting the electrical device 1, the possibility of the electrical device 1 failing is reduced, improving safety.

[0028] Fig. 2 shows an example of the power switch 22 and the switch control circuit 24. In this example, the switch control circuit 24 is realized by a push-pull solenoid 24a and a shutter 24b (holding member). Note that Fig. 2 shows a simplified representation of a push-type switch.

[0029] The push-pull solenoid 24a is controlled based on a determination signal output from the voltage determination circuit 21. A shutter 24b is attached to the shaft of the push-pull solenoid 24a, and the position of the shutter 24b changes depending on the state of the push-pull solenoid 24a.

[0030] Specifically, when the determination signal is at H level, the push-pull solenoid 24a maintains its pulled state, as shown in Fig. 2(a). At this time, the shutter 24b is maintained in a position where it does not contact the power switch 22. Therefore, when the power switch 22 is pressed by the user, it electrically connects the DC input jack 11 and the main circuit 13. In other words, the power switch 22 provides a normal on / off function.

[0031] On the other hand, when the determination signal is at L level, the push-pull solenoid 24a is controlled to a push state, as shown in Fig. 2(b). At this time, the shutter 24b is held in a position where it will come into contact with the power switch 22 when pressed (a position where it physically obstructs the power switch 22 so as to maintain a state in which the DC input jack 11 and the main circuit 13 are electrically disconnected). Therefore, even if the power switch 22 is pressed by a user, it is maintained in a state in which the DC input jack 11 and the main circuit 13 are not electrically connected. When the determination signal changes from L level to H level, the shaft of the push-pull solenoid 24a is returned to its original position by a return spring (not shown) or the like.

[0032] The push-pull solenoid 24a operates on power supplied from the battery 14. The configuration shown in Fig. 2 is one example, and the switch control circuit 24 may be realized by other circuit configurations that do not use the push-pull solenoid 24a.

[0033] The push-pull solenoid 24a normally generates an operating sound when it is in operation. Therefore, if the push-pull solenoid 24a operates due to an abnormality in the input voltage, the user can be made aware of the abnormality in the input voltage by the operating sound. Therefore, although the switch control circuit 24 is not limited to the push-pull solenoid 24a, it is preferable that the switch control circuit 24 generates a sound when an abnormality in the input voltage occurs. In this case, the switch control circuit 24 includes the function of an alarm unit.

[0034] In the above-described embodiment, the power supply circuit 12 includes an LED light-emitting element to visually notify the user of an abnormality in the input voltage, but the present invention is not limited to this configuration. For example, the power supply circuit 12 may be configured to notify the user of an abnormality in the input voltage by sound. In this case, the power supply circuit 12 may include an acoustic element, such as a piezoelectric buzzer, that outputs an alarm sound instead of (or in addition to) the LED light-emitting element. Alternatively, the power supply circuit 12 may be configured to output a voice guide indicating an error. Even with these configurations, the user can immediately notice that the AC adapter 15 connected to the electrical device 1 is inappropriate. Furthermore, this configuration can more reliably notify the user that the AC adapter 15 is inappropriate, compared to a configuration using only the LED light-emitting element.

[0035] Furthermore, as shown in FIG. 3 , the power supply circuit 12 may include a communication module 25 configured to transmit a wireless signal indicating an abnormality in the input voltage to a pre-designated information processing device 30. In this case, the communication module 25 transmits the wireless signal to, for example, the information processing device 30 recorded in the connection history. Here, the information processing device 30 is, for example, the user's smartphone or personal computer. Upon receiving the wireless signal from the communication module 25, the information processing device 30 displays a message indicating an abnormality in the input voltage of the electrical device 1 on its display screen. For example, a message such as "Please check the AC adapter" may be displayed. Therefore, even with this configuration, the user can immediately notice that the AC adapter 15 connected to the electrical device 1 is inappropriate. Furthermore, this configuration allows the display of a verbal message, thereby reliably informing the user of the reason why the electrical device 1 is not operating. The communication module 25 operates on power supplied from the battery 14.

[0036] Furthermore, in the above embodiment, both cases where the input voltage is overvoltage and undervoltage are monitored, but the present invention is not limited to this configuration. For example, the power supply circuit 12 may be configured to notify the user of an alarm only when the input voltage is overvoltage.

[0037] The above-described embodiments are illustrative examples provided to facilitate understanding of the invention. The present invention is not limited to these embodiments and encompasses various modifications and alternative forms of the above-described embodiments. For example, each embodiment may be embodied by modifying its components without departing from its spirit and scope. Various embodiments may also be implemented by appropriately combining multiple components disclosed in the above-described embodiments. Furthermore, various embodiments may also be implemented by deleting some components from all the components shown in the embodiments or by adding some components to the components shown in the embodiments. In other words, various modifications and changes are possible for the power supply device, the notification method, and the electrical device without departing from the scope of the claims.

[0038] The inventions described in the claims of the present application as originally filed are as follows: [Appendix 1] a voltage determination circuit that determines whether a voltage applied via a jack of the electrical device is outside a preset allowable voltage range; a power switch that electrically connects or disconnects the jack and a main circuit of the electrical device in response to a user's operation; a switch control circuit having a holding member that holds the power switch so as to electrically disconnect the jack from a main circuit of the electrical device when it is determined that the voltage is outside the allowable voltage range; A power supply circuit comprising: [Appendix 2] a notification unit that, when it is determined that the voltage is outside the allowable voltage range, notifies a user that the voltage is outside the allowable voltage range. 2. The power supply circuit according to claim 1, [Appendix 3] The notification unit A light-emitting element; a circuit that causes the light-emitting element to emit light when it is determined that the voltage is outside the allowable voltage range. 3. The power supply circuit according to claim 2, [Appendix 4] The notification unit outputs an alarm sound when it is determined that the voltage is outside the allowable voltage range. 4. The power supply circuit according to claim 2 or 3. [Appendix 5] The notification unit transmits a wireless signal indicating an alarm to a pre-designated information processing device when it is determined that the voltage is outside the allowable voltage range. 5. The power supply circuit according to any one of claims 2 to 4. [Appendix 6] The voltage determination circuit determines whether the voltage is outside the allowable voltage range by generating a determination signal. 6. The power supply circuit according to any one of claims 1 to 5. [Appendix 7] A printing device comprising the power supply circuit according to any one of appendices 1 to 6. [Appendix 8] determining whether a voltage applied through a jack of the electrical device is outside a preset allowable voltage range; When it is determined that the voltage is outside the allowable voltage range, a power switch that electrically connects or disconnects the jack and the main circuit of the electrical device in response to a user's operation is held by a holding member so as to electrically disconnect the jack and the main circuit. 10. A device protection method comprising: [Appendix 9] A main circuit, a jack into which a plug for supplying current via an adapter is inserted; a voltage determination circuit that determines whether the voltage applied through the jack is outside a preset allowable voltage range; a power switch that electrically connects or disconnects the jack and the main body circuit in response to a user's operation; a switch control circuit having a holding member that holds the power switch so as to electrically disconnect the jack and the main circuit when it is determined that the voltage is outside the allowable voltage range; Electrical equipment comprising: [Explanation of symbols]

[0039] 1: Electrical equipment, 11: DC input jack, 12: Power supply circuit, 13: Main circuit, 14: Battery, 15: AC adapter, 21: Voltage determination circuit, 22: Power switch, 23: Notification unit, 24: Switch control circuit, 24a: Push-pull solenoid, 24b: Shutter, 25: Communication module, 30: Information processing device

Claims

1. a voltage determination circuit that determines whether a voltage applied via a jack of the electrical device is outside a preset allowable voltage range; a notification unit that notifies a user that the voltage is outside the allowable voltage range when it is determined that the voltage is outside the allowable voltage range; a power switch that electrically connects or disconnects the jack and a main circuit of the electrical device in response to an operation by the user; a switch control circuit having a holding member that electrically disconnects the jack from a main circuit of the electrical device when it is determined that the voltage is outside the allowable voltage range, and that switches the power switch to a state in which the user can turn it on / off when the voltage falls within the allowable range while the jack is electrically disconnected from the main circuit of the electrical device; Electrical equipment comprising:

2. The electrical device according to claim 1 , wherein the switch control circuit, when it is determined that the voltage is outside the allowable voltage range, makes the power switch physically unable to be pressed.

3. The notification unit A light-emitting element; a circuit for causing the light emitting element to emit light when it is determined that the voltage is outside the allowable voltage range.

2. The electrical device according to claim 1.

4. The notification unit outputs an alarm sound when it is determined that the voltage is outside the allowable voltage range.

2. The electrical device according to claim 1.

5. The notification unit transmits a wireless signal indicating an alarm to a pre-designated information processing device when it is determined that the voltage is outside the allowable voltage range.

2. The electrical device according to claim 1.

6. The voltage determination circuit determines whether the voltage is outside the allowable voltage range by generating a determination signal.

2. The electrical device according to claim 1.

7. determining whether a voltage applied through a jack of the electrical device is outside a preset allowable voltage range; If it is determined that the voltage is outside the allowable voltage range, notifying a user that the voltage is outside the allowable voltage range; When it is determined that the voltage is outside the allowable voltage range, the jack and the main circuit of the electrical device are electrically disconnected, and when the voltage changes to within the allowable range while the jack and the main circuit of the electrical device are electrically disconnected, a power switch that electrically connects or disconnects the jack and the main circuit of the electrical device is set to a state in which the user can turn it on / off.

10. A device protection method comprising:

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